Bidirectional utilization of blockchain and privacy computing: Issues, progress, and challenges

With the rapid development of information technology and the increasing popularity of personalized services, the flow of users' personal information in the Internet is inevitable between different platforms and applications, which greatly affects the trust relationship in the digital society. In recent years, an increasing number of researchers have been dedicated to exploring the applications of blockchain and privacy computing technologies in the process of data value release. Scholars have discovered that the combination of the two technologies can alleviate many pain points of each other. Specifically, privacy computing is a computational theory and method for protecting privacy of information throughout its lifecycle. Privacy computing enables the processing, analysis, and computation of data while preserving the confidentiality of the original information. Nevertheless, challenges related to data ownership and benefit distribution impede the establishment of a fair and effective collaborative environment among multiple parties, thereby restricting its further practical development. On the other hand, blockchain is a technology for establishing a trusted platform among mutually untrusted parties, characterized by decentralization, immutability, traceability, and incentive mechanisms. However, blockchain also faces security issues such as transparency of on-chain data and lack of protection in smart contract execution environments. Therefore, this paper aims to comprehensively analyze and explore the integration of blockchain and privacy computing from both perspectives, focusing on bidirectional utilization. We systematically categorize and summarize relevant literature in this field, employing problem-oriented approaches. Finally, we identify the existing challenges and propose potential improvement methods in this field.